Catheters are placed inside blood vessels and body cavities, typically by being slid over guidewires. During placement, some way is needed to prevent backflow of blood or other fluid from the proximal end of the catheter. Many times it is also desirable, with minimum steps and effort, to attach a hand syringe to the proximal end of the catheter, open the catheter valve, inject fluids through the catheter and then remove the syringe and close the system. Many other applications require closure of a through-passage to, for example, control the flow of fluids as by a stopcoak or to grip a device, such as a guidewire, to provide a handle to enable working the wire to achieve its insertion and accurate placement in the body.
While it is well known to use luer fittings for attachment of medical instruments, e.g. a syringe to a catheter, valves controlling flow that use luer fittings generally do not have through-passages and also, for the most part, require separate activating motions.
The attachment of an external instrument such as a syringe to the passageway of a closure device in a manner that also opens the closure device is also known, but in a form that has had significant limitations. Such a device, for example, is described in U.S. Pat. No. 4,243,034. The described device relies on an axial sliding motion for making the attachment and opening a valve by releasing one or more balls from depression into the wall of a resilient tube. This device is neither as simple nor as effective as desired by those in the field, and also fails to meet all needs for single-handed operation in flow-control devices.
Other known closure or wire-gripping devices provide partial benefits but fail to combine all desirable features in one unit. For example, one type of device, known as a Tuohy-Borst closure, comprises a cap which, when screwed on, axially compresses a captured thick-walled tubular segment (a grommet) to seal a passage through the tubular segment. This device is disadvantageous in that it requires many turns to seal the passage.